A few nights ago, I enjoyed blues guitarist Dana Hubbard’s performance at a great house concert hosted by Mike and Wendy. Might I suggest listening and watching Dana playing on YouTube before going on with my writing? Music’s dynamic, not static – pay attention to Dana’s movements. Of course, the hands interact with the guitar. But, his entire body is involved. He’s also singing and speaking – which are two different actions. A lot is going on, and I will try to explain some neuroscience related to blues guitar.
So, I’ve got a front-row seat by happenstance. Mike announced that there was a great seat in front. We are all reluctant to sit in the front row, just like in elementary school! Mike called a few of us by name, and up we went to the best seat in the house. Dana is about five feet away. The first set is excellent, with some original, creative music. Dana has more than a trace of Robert Johnson in his music. So glad to be hearing some live music again.
I talked to Dana during the break; I got a couple of CDs. This whole evening has been great. Saw old friends from years ago. Some stories were joyful, others sad. A lot was swirling through my head as I sat down for the second set. I started thinking about what was going on in Dana’s brain to produce this wonderful music? What is the neuroscience of the blues? I was in a trance; someone asked me if I was falling asleep. I was in the opposite of a sleep state, trying to recall what was going on in Dana’s brain to produce this music. Let me step you through some of the details. It’s been a few years since I studied this; I’m sure I will make a few mistakes, but I will try to give you some idea of what’s involved in playing the blues guitar.
Here’s an image of Dana playing the guitar. I notice Dana’s complicated finger and hand movements; the complex dance between human and guitar. A neuroscientist calls this volitional (voluntary) motor control. Dana also was singing and speaking – a whole different set of neural processes. As he plays and sings, Dana listens and applies feedback. Dana’s using his auditory pathway to hear the music, and so is his audience. Finally, notice the smile on Dana’s face – emotions are also in play.
I’m self-taught in neuroscience. One of my favorite classes was Medical Neuroscience, taught by Professor Leonard White of Duke University. Here’s my textbook and my black notebook from the class. I spent four good months in 2013 studying Professor White’s lectures, the text, and my research notes. My notes attempt to capture a systems engineering view of the brain.
So, let me see what I can explain about the neuroscience of the blues. First, let’s consider how Dana plays the guitar – motor control. Check out the block diagram on the upper page of my notebook. Dana’s motor cortex is planning, initiating, and directing his hands and fingers to play the music. The Basal Ganglia is an input that helps figure out when to start moves. By the way, the Basal Ganglia is also a vital component of emotional response. See that sly smile on Dana’s face: Basal Ganglia feeding another part of the motor cortex, another set of separate but linked movements. The pathways are descending via efferent motor neurons; this means the information flow is from the brain to the body via nerve cells that control skeletal muscles. The Cerebellum provides a coordinated sense of movement; it feeds into the motor neuron network. Meanwhile, Dana’s brainstem keeps Dana’s posture upright on the stool.
There’s another essential piece to Dana’s music-making: Sensory-Motor Integration. Have a look at the diagram on the bottom page. We can start at the green box on the lower left; Internal & External Environment. Dana must hear what he’s playing; he wore a single earbud to listen to what he’s playing. Maybe his guitar is out of tune; perhaps he needs to adjust the equalizer, these call for some form of adapting to the external environment. Similarly, maybe Dana feels chilly; he would sense a change in his internal environment.
Dana’s senses pick up this information and send it up via ascending paths using afferent sensory neurons. The sensory info feeds to various areas of his brain. Sensory data is then coordinated and integrated across the brain. After all the information is combined, the motor components take action. For example, if his guitar needs tuning, then somatic motor control will fire various skeletal muscles. As a result, Dana adjusts his guitar. Dana’s body may make automatic visceral adjustments if the room is chilly, such as constricting blood vessels near the skin.
Let’s get back to volitional control; in other words, movements that we will our body to make. These movements arise in the primary motor cortex. A neuroscientist would express the activity of Dana’s fingers playing the guitar as fine control of his distal extremities. On the left side of the diagram, playing guitar stems from the primary motor cortex down the lateral corticospinal tract to motor neurons that control the fingers. Meanwhile, the medial pathway governs movements such as sitting. On the other side of the diagram, different types of activity are nonvolitional, for example, Dana’s genuine smile. Guess what; a whole separate pathway. I’ll skip those details except to say that these two sides get linked together in the little purple box – the Brainstem Reticular formation. Some speculate this is the area where consciousness arises. For entertainment, ask two neuroscientists to explain consciousness; sit back and watch the sparks fly.
Now, you might wonder what a cerebral cortex is? The word cortex derives from the Latin word for an outer layer, such as the bark of a tree. The outer layer folds up in our brain. It would be like a thin, medium-size pizza crust if we spread it out on a table. The cerebral cortex contains most of our higher-order functions that compose conscious thinking: movement, speech, singing, and vision come to mind (yes, the pun was intentional). In the upper left corner of the diagram, you can see a cartoon of the motor cortex. The motor cortex is a strip of the brain about the dimensions of your finger. The upper extremity (arm) is in the middle of the motor cortex. The motor cortex is contralateral; the left motor cortex controls the right side of the body. Since Dana uses both hands to play the guitar, he’s using both sides (hemispheres) of his brain to play.
Another critical point in the diagram, a single neuron can cause multiple muscles in the arm to either flex or relax (extend). Translated to neuro speak: A single action potential (AP) in a corticospinal neuron activates four muscles in a forelimb. We learn all this complex behavior over time. We can acquire new motor skills because our brain is dynamic, flexible, and plastic.
I covered just a few highlights of what’s happening when Dana plays the blues on this guitar. I want to discuss how the audience (and Dana) listen and react to the blues in a future piece. Meanwhile, I need to get up and use my motor cortex to get some exercise!